STAINING, PRACTICAL AND THEORETICAL 



2. Differentiate for a few seconds in formalin till the bright red 

 colour changes to a clear deep pink ; then wash with tap water. 



3. Counterstain one to five minutes in Solution B until the sec- 

 tion appears purplish yellow to the naked eye ; then wash with tap 

 water. 



4. Differentiate in 95% alcohol until the section appears red; 

 then wash in tap water. 



5. Stain for about five minutes in Solution C ; then wash in tap 

 water. 



6. Stain for one minute in Solution D ; then, without washing, 

 blot dry. 



7. Treat in Solution E until no more colour comes out. 



8. Pass through two changes of xylol; then mount. 



Results: 



Gram-positive organisms: blue. Gram-negative: red. Tissues: 

 varying shades of red and purple. 



Reference: MacCallum, W. G. (iqiq)- 



MALLORY'S STAIN - HAEMATOXYLIN 

 For the differential staining of the pancreatic islets 



Solutions required: 



A. Distilled water 100 ml. 



Sulphuric acid cone. . . . . i ml. 



Potassium Permanganate . . . . i gm. 



B. Harris or Ehrlich haematoxylin. 



C. Lithium carbonate, saturated aqueous. 



D. Acid Fuchsin acetic (Mallory) 0-5% aqueous. 



E. Phosphomolybdic Aniline Blue - Orange G 

 (Mallory). 



Technique : 



1. Mammalian pancreases are fixed in Bouin and afterwards 

 washed in 80% alcohol. 



2. Dehydrate, clear, and embed in paraffin wax. 



282 



